1. Technical Field
The present invention provides and improved data processing system and in particular a method and apparatus for accessing applications. Still more particularly, the present invention provides a method and apparatus for accessing legacy applications in a distributed data processing system through a display emulation mechanism.
2. Description of Related Art
The Internet, also referred to as an xe2x80x9cinternetworkxe2x80x9d, is a set of computer networks, possibly dissimilar, joined together by means of gateways that handle data transfer and the conversion of messages from the sending network to the protocols used by the receiving (with packets if necessary). When capitalized, the term xe2x80x9cInternetxe2x80x9d refers to the collection of networks and gateways that use the TCP/IP suite of protocols.
The Internet has become a cultural fixture as a source of both information and entertainment. Many businesses are creating Internet sites as an integral part of their marketing efforts, informing consumers of the products or services offered by the business or providing other information seeking to engender brand loyalty. Many federal, state, and local government agencies are also employing Internet sites for informational purposes, particularly agencies which must interact with virtually all segments of society such as the Internal Revenue Service and secretaries of state. Providing informational guides and/or searchable databases of online public records may reduce operating costs. Further, the Internet is becoming increasingly popular as a medium for commercial transactions.
Currently, the most commonalty employed method of transferring data over the Internet is to employ the World Wide Web environment, also called simply xe2x80x9cthe Webxe2x80x9d. Other Internet resources exist for transferring information, such as File Transfer Protocol (FTP) and Gopher, but have not achieved the popularity of the Web. In the Web environment, servers and clients effect data transaction using the Hypertext Transfer Protocol (HTTP), a known protocol for handling the transfer of various data files (e.g., text, still graphic images, audio, motion video, etc.). The information in various data files is formatted for presentation to a user by a standard page description language, the Hypertext Markup Language (HTML). In addition to basic presentation formatting, HTML allows developers to specify xe2x80x9clinksxe2x80x9d to other Web resources identified by a Uniform Resource Locator (URL). A URL is a special syntax identifier defining a communications path to specific information. Each logical block of information accessible to a client, called a xe2x80x9cpagexe2x80x9d or a xe2x80x9cWeb pagexe2x80x9d, is identified by a URL. The URL provides a universal, consistent method for finding and accessing this information, not necessarily for the user, but mostly for the user""s Web xe2x80x9cbrowserxe2x80x9d. A browser is a program capable of submitting a request for information identified by an identifier, such as, for example, a URL. A user may enter a domain name through a graphical user interface (GUI) for the browser to access a source of content. The domain name is automatically converted to the Internet Protocol (IP) address by a domain name system (DNS), which is a service that translates the symbolic name entered by the user into an IP address by looking up the domain name in a database.
The Internet also is widely used to provide users access to applications through browsers. Access to applications on the Web is commonly provided through the use of programs known as xe2x80x9cappletsxe2x80x9d, which may be embedded as objects in HTML documents on the Web. Applets are Java programs that may be transparently downloaded into a browser supporting Java along with HTML pages in which they appear. These Java programs are network and platform independent. Applets run the same way regardless of where they originate or what data processing system onto which they are loaded.
Numerous legacy applications, however, still exist, which cannot be easily accessed across the Web. A legacy application is an application that has been in existence for some time. The term often refers to mainframe and enterprise resource planning (ERP) applications. In today""s world of the Internet, virtually anything not Web related is often thought of as a legacy application. These applications are still used by many businesses and provide access business data, such as financial information, customer lists, personnel records, and manufacturing reports. Many businesses desire to provide access to these applications for use by employees and customers across the Web.
The use of mainframe systems as a Web server to provide access to applications is becoming more common. The legacy applications on these types of systems, however, provide user interaction through a xe2x80x9cgreen screenxe2x80x9d. A xe2x80x9cgreen screenxe2x80x9d is a display using green characters on a dark background. Access to these applications has been provided through the use of a terminal emulation, which requires the installation of emulator software or downloading of an applet on the client. In other cases, HTML versions of xe2x80x9cgreen screenxe2x80x9d have been created for transmission to browsers in clients. An HTML document is created for each screen in an application. Creation of HTML versions of these screens however, is tedious and time consuming.
Therefore, it would be advantageous to have an improved method and apparatus for providing access to legacy application over the Web.
The present invention provides a method and apparatus for accessing an application. Data from a host application is transformed from a host format to a markup language format to form markup language data. A stylesheet is applied to the markup language data to generate a markup language document. This markup language document is then presented on a display on which user interaction may occur. Multiple stylesheets can be used to provide different displays for the same host application data.
In response to receiving input to the markup language document, this input is transformed into the host format and returned to the host application. In this manner, the mechanism of the present invention provides access to a legacy application.